There are two overarching goals for the Neuropathology Core. The first involves neuropathological evaluation of brain tissue obtained at autopsy on subjects in the Program Project. These analyses will be performed: (1) to provide a neuropathological diagnosis on all subjects who come to autopsy, (2) to perform quantitative neuropathological data on all subject who come to autopsy, and (3) to perform biochemical analysis for Abeta and synaptophysin on the brain samples of all subjects who come to autopsy. In addition, Core D will evaluate Abeta 40 and Abeta42 in plasma samples that are collected annually, to determine if these measures can serve as biomarkers of 'conversion' to AD.